A known conventional large-capacity storage apparatus, which is a type of electronic apparatus, includes many storage devices such as hard disk drives. FIGS. 1A, 1B, and 1C illustrate an example of related art of this type of large-capacity storage apparatus. In the large-capacity storage apparatus 1 in these drawings, many hard disk drives 2 are mounted side by side at one end of the cabinet of the large-capacity storage apparatus 1. A control unit 3 and a power supply unit 4 are placed at a central portion of the cabinet of the large-capacity storage apparatus 1. A blower fan 5 for use in air cooling is provided at another end of the cabinet of the large-capacity storage apparatus 1. The blower fan 5 inhales cooling air, which is supplied from the side on which the hard disk drives 2 are mounted, from above, and exhales the air to the back. A backplane 6, which is a partitioning wall, is provided between the hard disk drives 2 and the control unit 3 and power supply unit 4. The control unit 3 and power supply unit 4 are duplicated, forming a redundant structure.
The large-capacity storage apparatus 1 having this type of structure has been problematic in that since a large amount of air is used to cool the hard disk drives 2 and the blower fan 5 thereby has a large blowing capacity. This has increased fan noise and has caused the blower fan 5 to consume much power. In view of this, a technology to cool heat-generating electronic parts by use of a water-cooling device instead of air cooling is described in, for example, Japanese Laid-open Patent Publication No. 5-267875. With the water-cooling device, intended for a printed-circuit board, described in Japanese Laid-open Patent Publication No. 5-267875, a fitting plate is used to removably attach a water-cooling head to a printed circuit board. The water-cooling head is formed like a flexible bag, which is deformed so as to follow the outer shapes of parts mounted on the printed-circuit board. A coolant circulates in the water-cooling head. The water-cooling head is connected to a thermo transfer unit with a hose; after having circuited in the water-cooling head, the cooling water is cooled in the thermo transfer unit and is returned to the water-cooling head. A similar cooling-water device is proposed in, for example, Japanese Laid-open Patent Publication No. 7-245363. In this cooling-water device, a power semiconductor device is mounted on one surface of a semiconductor module attaching plate and a heat transfer plate in contact with a coolant is mounted on another surface of the semiconductor module attaching plate.